Output current measurement and protection apparatus used for chain type converter

Abstract

The invention discloses an output current measurement and protection apparatus used for a chain type converter. The output current measurement and protection apparatus comprises a current sensor, an A / D conversion and overcurrent protection module, an FPGA chip, a communication module and a power module, wherein the current sensor is mounted beside any one chain link module of a tested chain type converter; and an alternating current output end connecting line of the chain link module directly passes through a primary side measurement hole of the current sensor; the secondary side output end of the current sensor is connected with the FPGA chip through the A / D conversion and overcurrent protection module; and the FPGA chip is connected with the communication module. According to the output current measurement and protection apparatus, the primary side and the secondary side of the current sensor do not need to bear a high voltage, thereby solving the problem of voltage withstand of the sensor; the FPGA chip is used for sampling an output current and an overcurrent protection signal, and the measured current and overcurrent protection data are transferred in a serial communication manner through optical fibers, thereby realizing high-speed sampling and overcurrent protection, and satisfying requirements of real-time feedback and control of the output current; and therefore, the problem in rapid measurement and protection of the output current of the high-voltage chain type converter is effectively solved.

Description

technical field [0001] The invention relates to electrical automation equipment, in particular to an output current measurement and protection device for chain-type converters. Background technique [0002] The chain-type converter is also called the H-bridge series converter, which is composed of the AC output of multiple chain-link modules (or single-phase H-bridge converter modules) in series, and can be widely used in various In the conversion device, such as high-voltage frequency conversion speed controller, new static synchronous compensator (STATCOM), new energy power generation inverter, dynamic voltage restorer (DVR), active filter (APF), etc. [0003] Since chain-link converters are often used in applications with high output AC voltage (3kV-35kV), it becomes difficult to measure and protect their output current. When the Hall current sensor is used to measure the output current, due to the limitation of the insulation withstand voltage of the primary and seconda...

AI Technical Summary

Problems solved by technology

[0003] Since chain-link converters are often used in applications with high output AC voltage (3kV-35kV), it makes it difficult to measure and protect the output current

When the Hall current sensor is used to measure its output current, due to the limitation of the insulation withstand voltage of the primary and secondary sides of the Hall current sensor, it is impossible to directly measure the output current of the chain-link converter in higher voltage applications.

However, the use of high-voltage current transformers leads to high measurement costs, and the DC component in the output current of the converter cannot be measured, which affects the control performance

Also, the output current may need to be used for feedback control, and the sampling rate may need to be as high as 50us a little

Images